Thanks Thorn.
I am doing some measurements as I find them of the various Selle models (5 of this style) and other similar seats with such cut-outs. Then I'm going to go and talk to a couple of the LBSs and see what they can do for me.

You know, I hadn't even thought of contacting Selle themselves - rather obvious but it hadn't occurred to me. Thanks for that prompt, Thorn. I'll do that too.

I really need to do something. I have been puzzling about why this is suddenly an issue as my current saddle (same on both my bikes) has been comfortable til now , and my only conclusion is that along with a slight increase in time in the saddle, I must also be out-putting more power in my specific training and am def outputting more power in my racing. More power must equal more pressure on parts of my body including how I sit on the saddle...